Sand exclusion screen assemblies are employed in wellbores during the production of hydrocarbon fluids from subterranean formations. Conventional sand screen assemblies include a perforated base pipe, a drainage layer, a filter medium, and a protective jacket or shroud. Such screen assemblies are designed to filter out particles, such as formation sand or placed gravel/proppant, while facilitating the passage of hydrocarbon fluids into the wellbore. One drawback in the deployment of such screen assemblies is the erosion of the filter medium by particle impingement contained in the fluids that pass the screen assemblies. The presence of particulate in the flow stream, coupled with the current designs and manufacturing methods of the screen assemblies, can cause erosion. For instance, current designs and manufacturing methods minimize the space, or offset, between the sand screen components for a number of reasons, which can increase erosion of the filter medium. For example, the offset between conventional shrouds and the filter medium is not controlled and the shrouds are susceptible to deformation and/or radial movement, which can cause the shroud to interface with the filter medium at various locations away from the welds at the ends of the base pipe. Since conventional shrouds may have perforated holes, these holes cause a flow concentration that localizes and increases the erosion of the filter medium resulting from an inadequate amount of flow dispersion due to the interface between the shroud and the filter medium. When the filter medium becomes eroded, then particles are produced from the well, which is highly undesirable. Production of these particles can cause excessive erosion of production tubulars, downhole equipment and surface equipment, and lead to high maintenance costs and undesirable downtime of wells.
Accordingly, a need has arisen for a sand control screen assembly that is capable of filtering fines out of a production stream from a subterranean hydrocarbon bearing formation and that does not readily suffer from erosion.